Compared with osteoarthritis patients, individuals with rheumatoid arthritis who undergo total knee replacement surgery have lower expectations about their postsurgical outcomes, according to a new study by researchers at Hospital for Special Surgery (HSS) in New York City. These reduced expectations, which may be unnecessary, could cause some patients to slack on their postsurgical rehabilitation leading to worse outcomes, say doctors. The study will be presented November 7 at the annual meeting of the American College of Rheumatology.

"If rheumatoid arthritis patients are healthy enough to have surgery, they should really expect good outcomes. If patients have lower expectations, then maybe they don't push their physical therapy, and perhaps don't recover as well," said Lisa Mandl, M.D. M.P.H., a rheumatologist at HSS who was involved with the study. "It would be a real shame if these patients could have significantly improved function, but for some reason they don't attain it, perhaps connected to their expectations."

Before this study, researchers had known that patients with rheumatoid arthritis (RA) who undergo a total knee replacement are often very satisfied with the surgery, even though they have inferior outcomes to patients with osteoarthritis who undergo the operation. Because satisfaction is determined not only by improvements in pain and function, but by fulfillment of pre-operative expectations, investigators set out to determine if the expectations of the two patient groups differed.

The researchers turned to the HSS Total Joint Replacement Registry, a prospective registry started in 2007 that includes, among other things, data on all patients who seek care at HSS for knee replacement surgery, also known as total knee arthroplasty (TKA). Because roughly 90 percent of patients who undergo TKA have osteoarthritis, they first used the registry to identify patients with RA. They then mined the registry to find osteoarthritis patients that matched these RA patients in terms of age, gender and function. Investigators gauged function using the Lower Extremity Activity Score (LEAS), a score that quantifies how much activity a person is capable of performing. The scale ranges from a person being confined to bed all day to participating in vigorous physical activity such as competitive level sports.

The researchers identified 62 RA patients and matched them to 124 osteoarthritis controls; 81.7 percent were women and the average age was 64.7 years. The average LEAS was 8.7, which corresponds to being able to walk around the house and for several blocks without assistance.

The investigators measured pain, stiffness and function prior to surgery, using a tool called the Western Ontario and McMaster Universities Arthritis Index (WOMAC), and found that patients with RA had worse scores. "Even when you try to match these patients to make them similar, it really does seem like this chronic disease makes these patients sicker, less happy, less functional and clearly they have worse expectations," Dr. Mandl said.

The investigators measured patient expectations prior to surgery using a validated tool called the Hospital for Special Surgery Expectations Survey, with 100 being the highest score and 0 being the lowest. RA patients had a lower overall expectation score compared with osteoarthritis patients, 73.7 versus 79.8, a difference that was statistically significant (P=0.03) and clinically meaningful. Patients with RA also had statistically significant lower expectations for several individually measured items such as whether the surgery will improve the ability to walk short distances, improve the ability to go up stairs, improve the ability to perform daily activities such as household chores and improve the ability to exercise.

"When people report if they are satisfied, a lot of it is not just related to actual objective measures. It has to do with their expectations preoperatively. So, if you don't expect much and you don't get much, you could be pretty happy," said Dr. Mandl. "You might have a person who says, 'I would love to have this surgery and be able to get up and walk to the bathroom without pain.' And when they have their surgery, they can get up and walk to the bathroom without pain, but maybe because that is all they expected, they kind of give up after that. They might not be optimizing their postoperative physical therapy."

"Our rheumatoid arthritis patients have just come along extraordinarily in the last decade with, first, the widespread use of traditional medications and now the more widespread use of the potent biological medications," said Susan Goodman, M.D., a rheumatologist at Special Surgery. "What we can do as doctors is ensure that we educate our patients properly. In the past, our rheumatoid arthritis patients didn't do as well as other patients and those expectations were realistic, but I think times are changing. RA patients might think 'oh, I'm never going to have great function, why am I pushing myself?' That would be shortchanging themselves. Doctors should explain to RA patients that they should expect good outcomes."

According to Dr. Mandl, doctors should assess patients' preoperative expectations. "If they are concerned that patient's expectations are not in line with what they would predict, then doctors should recalibrate what the patient is hoping for, so that they can get the best result they can," she said.

Dr. Mandl says the study also makes her wonder if patients with RA are not choosing to have surgery because they don't think it will make a difference.

RA is an autoimmune disease that causes joint swelling, pain and fatigue among other symptoms. Osteoarthritis is caused by the normal wear and tear of the aging process; it can be encouraged by a high impact injury or obesity.

The HSS Total Joint Replacement Registry was initially funded by the Agency for Healthcare Research and Quality Centers for Education and Research on Therapeutics.